Andy Murray believes Laura Robson's elevation to junior number one is a sign of things to come for the youngster.

Robson burst on to the scene by winning the Junior Wimbledon title last summer - impressing both with her mature play and personality.

She also reached the girls' final at the Australian Open in January and her promise was confirmed this week when she topped the rankings for the first time.

Robson, who lives in Wimbledon, is also the youngest player in the top 30 and British number one Murray believes she has what it takes to replicate her success in the senior ranks.

He said: "I think she's very good. I think she will for sure get into the top 50. But after that, you don't know. Anything can happen.

"I know she's had a few problems here and there with injuries because she's been growing a lot, which is normal around that age.

"But, I mean, she's going to be good. It's just you can never say how good someone is going to be. To be number one in the world, I think it's an awesome achievement.

"For sure, in the guys, if you get to number one in the world in the juniors you're going to be a top player pretty much.

"And the girls, if you do it when you're 18 it's not quite the same. She's doing it so young - it shows she's going to be good."

Murray will attempt to avenge his Australian Open defeat by Fernando Verdasco when he takes on the Spaniard in the quarter-finals of the Sony Ericsson Open in Miami.

The world number four was joint favourite to capture his first grand slam title in Melbourne but came unstuck against an inspired Verdasco in the fourth round.

Murray had beaten the big-hitting Spaniard in all their five previous meetings but Verdasco, given new belief by his role in helping Spain win the Davis Cup, turned the tables.

He went on to reach the semi-finals, where he lost to Rafael Nadal in one of the great matches, and Murray will have to be at his best to progress.

The Scot can certainly expect a tougher challenge than he was given in the fourth round on Tuesday when Victor Troicki capitulated to a 6-1 6-0 defeat.

Murray, meanwhile, will hope he does not need to rely on challenging line calls after it was revealed he has one of the lowest success rates.

The 21-year-old has only managed to overturn 25% of the 224 calls he has challenged since the Hawk-eye system was first introduced in Miami three years ago.

Novak Djokovic leads the way among the top men with a 55% success rate while Nadal and Roger Federer fare slightly less well with 36% and 39%, respectively.